1. Field of the Invention
The present invention relates to modular telecommunication equipment and, more particularly, to a card mounted radio transceiver and/or modem for use in establishing a link to a wireless network for electronic equipment such as personal computers.
2. History of the Prior Art
The fields of both data processing and telecommunications have experienced marked advances in recent years. Personal computers have become smaller and more efficient in their progression through desktop, laptop, notebook, and palmtop versions. The great advances in microprocessors, memory chips and miniaturization techniques have also enabled more and more computing power to be packaged in smaller and smaller spaces.
Personal computers are manufactured by many different suppliers around the world. An entire industry has subsequently developed in supplying memory cards for enhancing the capacity of this wide variety of personal computers. Recently, there has been a movement toward standardizing the interconnection formats for use in circuit cards for personal computers. In particular, the PC and Memory Card International Association (PCMCIA) was formed with the goal of promoting the interchangeability of integrated circuit and memory cards among computers and other types of electronic products. Toward this end, the PCMCIA has promulgated certain physical and electrical standards to ensure that cards will be able to be used in different pieces of equipment. Both data storage, i.e. memory, and peripheral expansion, i.e. I/O, card types constructed in accordance with standards should be able to be used in any connectors also constructed in accordance with the standards. Such a standard is set forth in a variety of documents including the PCMCIA PC Card Standard, Release 2.0, incorporated by reference herein. The standard sets forth a 68 pin interchange for I/O type circuit cards for use in PCs.
Advances in wireless telecommunications have also moved rapidly in recent years. Various communication standards have been promulgated around the world defining specific frequencies, data rates, data formats, and the like for both voice and data communications by radio links between base stations and mobile units. For example, specialized packet switching systems for mobile data communications have enabled portable computers to directly uplink data access into the landline data communication network. Similarly, conventional voice based cellular radio systems, both analog and digital versions, can receive data from portable computers and transmit that data through the conventional telephone network to a remotely located data terminal. In addition, other systems such as paging (both local and global), DECT (Digital European Cordless Telecommunications), Mobitex, CDPD (Cellular Digital Packet Data), PCS (Personal Communications System) and the like have come into recent use. Each of these wireless telecommunications formats and standards generally requires separate software to provide a gateway for data into the wireless network as well as separate transmission/reception formats. This allows communication with radio base stations operating in different geographic areas as well as parts of different networks. It would be desirable, however, to package radio transceivers and/or modems in a modular manner so that a telecommunications terminal, such as a portable telephone or a portable personal computer, could be adapted for communication with different systems by simply replacing the modular unit with one which was especially configured for the telecommunications network with which communication was desired.
The use of card mounted telecommunications interface equipment in a PC has existed for some time. In particular, modems are frequently mounted on an I/O card and plugged into receiving receptacles within the PC. The modem then enables the interface of a PC with standard telecommunication network lines and the transmission/reception of data for those lines. This is an extremely useful tool and maximizes the usefulness of the PC.
More recently, the company GEC PLESSEY developed a radio transmitter for a wireless local area network (WLAN) for a standard card engagement with a PC so that data can be transmitted within approximately a hundred meters with a frequency band reserved for such activity. However, this radio transmitter for a wireless LAN does not incorporate the requisite flexibility and communications alternatives inherent in Applicant's present system which overcomes many of the disadvantages of the prior art.
It would be an advantage therefor to provide a standard PCMCIA card mounted radio transceiver which is readily replaceable in order to enable electronic equipment to communicate with various networks and in accordance with various radio standards merely by interchanging such a card. The system of the present invention and various components thereof provide such advantages.